Alcohol has a yin and yang. In low doses – a drink or two a day – it has potential health benefits. In high doses, it makes us wreck cars, hit on our friends' wives, and relieve ourselves in the swimming pools of total strangers.

But you don't need me to tell you about the perils of alcohol consumption. The key question on your mind, not to mention my own, is how much you can get away with drinking before small animals begin using your belly for shade on sunny days.

Does Alcohol Make You Fat?

Believe it or not, this isn't an easy question to answer.

Alcohol (a broader term for ethanol, or ethyl alcohol) is one of those substances that blurs the line between food and drugs. It's technically a macronutrient like carbs, protein, and fat, with seven calories per gram. (Carbs and protein have four calories per gram, and fat has nine.) And where you have calories, you should have usable energy.

But that's where it starts to get tricky.

Contrary to what some college kids might believe, it's not an essential nutrient; the body doesn't need it for growth and survival, and, unlike cars with internal-combustion engines, humans can't use ethanol for fuel. Your body views it as a toxin, and fights to get rid of it once it's ingested. That's why it has a higher thermic effect than other macros, meaning it takes more calories to process than carbs, fat, or even protein.

But before I look into that in a bit more detail, here's some useful information to keep in mind. When we talk about alcohol in general, we talk about number of drinks per day or per week or per inning. But in research, we usually talk about grams of ethanol per day. Here's how to translate grams into number of drinks and total calories:

One study found that men consuming an average of 56 grams of ethanol per day (four beers) took in 16 percent more total calories than a matched group of non-drinkers. The two groups – drinkers and non-drinkers – had identical amounts of physical activity. (10) So, logically, you'd think that the drinkers packed on some pounds.

They didn't. Both groups had the same body-mass index, despite all those excess calories for the drinkers.

So does alcohol have a secret life as a fat-fighting superhero, cleverly masquerading as an addictive vice?

It's doubtful. Nobody's ever measured what would happen if you matched up two groups of drinkers and non-drinkers, consuming an equal number of total calories, and followed them over time.

One study compared two weight-loss diets (1,500 calories per day, or the equivalent of the crumbs from one of John Berardi's mid-morning snacks). In one diet, subjects got 10 percent of their total calories from white wine – 150 calories, or just over a glass per day. The other group got 10 percent from grape juice. (11) After three months, the white wine group lost almost a kilogram more total body weight (a kilogram is 2.2 pounds), although the difference wasn't statistically significant.

No one knows how this would work out over time. My guess is that the effect would probably be neutral. While alcohol stimulates more calorie expenditure, it also suppresses the oxidation of dietary fat – your body burns more calories but less fat.

That said, another line of research suggests that alcohol's activation of AMPk, a metabolism-regulating enzyme, helps you lose fat by increasing insulin sensitivity. (12,13)

Effects on Muscle Mass and Testosterone

Does alcohol destroy muscle mass? Maybe, but you have to drink a lot. Most of the human research on alcohol's effect on muscle-protein metabolism is on flat-out alcoholics who chronically consume more than 100 grams of ethanol – at least seven drinks – per day. Between one- and two-thirds of these drunks end up with "alcohol myopathy," a condition characterized by muscle weakness and atrophy, frequent falls, and difficulty walking. (14) The high alcohol intake tends to displace essential nutrients, which means casual drinkers aren't likely to lose their hard-earned muscle mass.

If you're one of those casual drinkers, don't get cocky yet: In another study, two to three beers per day was shown to lower Testosterone levels by 6.8 percent during a three-week period. (15) But even that news isn't necessarily bad. The beer also increased dehydroepiandrosterone sulfate (DHEAS) levels by 16.5 percent. DHEAS elevation has the potential to lower cardiovascular disease risk. We can only speculate over the impact of these results, since the researchers didn't measure the effects on performance or body composition.

Another study looked at the acute effect of alcohol intoxication on post-exercise hormonal response, using trained lifters as subjects. (16) After a workout, half the subjects were given the equivalent of five drinks. The researchers then monitored all the subjects' hormone levels for the next five hours. No differences were seen in Testosterone and other related hormones in either group. Cortisol was elevated in the ethanol group, but only for a short period.

Anecdotally, I know lots of athletes and bodybuilders who average two or three drinks a day and continue to get stronger and pack on muscle mass. The absolute most jacked guy I know drinks a bottle of red wine every night. (Compared to the rest of the stuff he's on, he probably considers it relatively safe.)

Would those guys make even better gains without the Two Buck Chuck? Maybe, but my hunch is that moderate alcohol consumption, or the absence of alcohol, has very little effect on the many variables that determine size and strength.

However, the story is different with endurance exercise. In one study, volunteers were worked to exhaustion on ergometers and then given the equivalent of 10 drinks. That suppressed Testosterone production. (17) Like all acute-effect studies, this one begs for a long-term version, examining the effects over a period of weeks or months – if for no other reason than to see endurance athletes chronically drunk (in the interest of science, of course).

But no ethics review board is going to approve a study like that, which brings me to the next point.

Effects on Exercise Performance and Recovery

If it's difficult to get approval for a study in which athletes get drunk after a workout, imagine how hard it would be to get a green light when lifters or runners get drunk before.

But, believe it or not, it has been done.

In one study, subjects were given the equivalent of about six drinks and then tested for strength and endurance. Actually, they were tested before, during, and 24 and 48 hours after ingesting the alcohol. (18) Contrary to what the researchers expected, the alcohol had no observable effect on any of the strength tests. Additionally, there was no increase in creatine kinase, an indicator of muscle damage.

In a similar study, the equivalent of about five drinks prior to testing had no effect on isometric strength, muscle stiffness, muscle soreness, or creatine kinase activity compared to the study's alcohol-free group. (19)

For endurance athletes, alcohol doesn't seem to interfere with glycogen replenishment after depletion. This is important when you consider that a runner or swimmer or cyclist might have multiple events in one day, or a heat in the evening followed by the finals the next morning. Any lag in recovery could be the difference between winning and losing. One study gave endurance athletes the equivalent of 10 drinks following a depleting workout. There was a statistically insignificant lag in glycogen resynthesis at the eight-hour mark, and none after 24 hours.

I guess it's encouraging to know that if a runner is stupid enough to slam down 10 drinks after a race when he knows he has another in eight hours, his body will still store enough energy to compete.

Storing up energy through alcohol is probably a bad idea.

Dehydration is another issue for athletes who like to get hammered the night before a game. Here's what you need to know: The more concentrated the alcohol source, the greater its ability to dehydrate.

In one study, for example, drinks containing 4 percent alcohol or more increased urine output. (21) That includes just about anything stronger than light beer. Hard liquor has an especially potent diuretic effect. For example, an ounce of an 80-proof beverage (40 percent ethanol) contains 10 milliliters of ethanol and 15 milliliters of water. Yet study subjects ended up pissing out 100 milliliters, or four times as much as they poured in. (22)

Binge drinking and performance generally don't mix well, but once again, it's endurance-type work that takes the biggest hit. Research on rugby players after a night of heavy drinking shows that aerobic performance suffers, while anaerobic performance isn't affected. (23) Score another one for our team.

What about Health Benefits?

My editor warned me that Testosterone Nation readers might not want to read about the long-term health effects of alcohol. Still, I think the subject is interesting enough to warrant a short detour from the subject of getting huge and veiny.

We all know that serious alcohol abuse brings with it the risk of addiction, liver disease, heart failure, and a life rich in fucked-upedness. Goes without saying, right? But on the flip side, moderate alcohol consumption seems to have measurable health benefits.

Moderate beer consumption (11 to 22 ounces per day) improved immune response in two recent studies. (1,2) Another study showed it improved concentrations of blood lipids. (3) Drinking three to four glasses of beer a day reduced C-reactive protein (linked to inflammation and heart disease) and fibrinogen (linked to blood clotting and thrombosis) by 35 percent. (4) This points to an anti-inflammatory mechanism that might partially explain the link between moderate drinking and lower risk of heart disease.

A variety of studies have shown the cardioprotective benefits of roughly one or two glasses of red wine per day. (5) The nutrients in wine (such as reservatrol and proanthocyanidin) and the alcohol benefit your heart in different ways. (6) The nutrients combat oxidative stress, while the alcohol improves vasodilation (opening up your blood vessels) and blood flow. Other benefits include increased HDL (the "good" cholesterol) and reduced platelet aggregation, better known as blood clotting. If you want to nit-pick over the best ways to protect your heart, darker varieties of beer and wine tend to have higher polyphenol content. (7)

There isn't a lot of data on the potential health benefits of hard liquor. But with the little we have, the benefits appear similar. Cognac, for example, was shown in one study to increase plasma antioxidant levels. (8) Cognac, Armagnac (a brandy similar to cognac), and bourbon are all rich in ellagic acid, an antioxidant with anti-microbial and anti-cancer properties. (9)

Beer in Mind...

So is beer our friend? Is wine a health food? Can you live longer by drinking more bourbon?

Bottom line, alcohol isn't essential for good heath, and there's no reason to think it improves your performance in anything. But at the same time, moderate drinking (up to two drinks a day) might help protect your heart without having a negative effect on your quest to look good naked.

If you don't already drink, there's no reason to start. And if you drink a lot, you risk a lot. But if you're a just-right drinker – you drink enough to enjoy the benefits without ever waking up with a hangover (or, worse, with a stranger who's equally hung over) – there's no reason to quit.

Maybe the simplest advice is this: If you drink so much that it interferes with your training, you need to cut back. If the amount you drink never interferes with anything important, let's get together for a beer sometime.

Alan Aragon is a nutrition consultant in Los Angeles who designs programs for recreational, Olympic, and professional athletes, including bodybuilders, figure athletes, and members of the Los Angeles Lakers, Los Angeles Kings, and Anaheim Ducks. He writes a column for Men's Health magazine, "Ask the Weight Loss Coach," as well as a monthly research review, which offers in-depth analysis of the latest studies on training, nutrition, supplementation.